OP III – 3 Using satellite observations to estimate exposure to flaring: implications for future studies of the health impacts of unconventional oil and gas operations

Abstract

Background/aim Unconventional oil and gas (UOG) operations may increase exposure to hazardous air pollutants and several studies suggest they can harm the health of nearby residents. However, research is hampered by a lack of data on pollutant emissions from drilling sites and few studies have examined the potential health impacts of flaring, the common practice of combusting petroleum waste products on site. Methods We utilise a novel remote sensing data source to estimate exposure to flaring among residents of the Eagle Ford Shale region of Texas, U.S. This rural region has experienced a roughly tenfold increase in oil and gas production since 2010 and is the highest oil-producing and fourth highest gas-producing region in the U.S. We investigate the potential of the VIIRS Nightfire product – which includes satellite observations of infrared radiation at night from combustion sources – to characterise exposure to flaring and compare estimates of exposure to UOG operations derived from VIIRS and those derived from more traditional data sources (permit and self-reported production data) that have been used in previous epidemiological studies. Results Nearly 8 00 000 people live less than 5 km from one or more of the 22 000 active, permitted UOG wells in the study region. Nighttime infrared observations from VIIRS confirm reports of extensive flaring in close proximity to homes. We construct VIIRS-derived indices to characterise exposure to flaring based on residential proximity to flaring locations, flaring frequency and duration, temperature of combustion, and areal extent. We discuss the strengths and limitations of these measures for estimating air pollutant emissions, and the implications of this exposure assessment method for future epidemiological research on the health impacts of UOG operations. Conclusion While previous studies have relied on self-reported information on the location, timing, and productivity of oil and gas extraction activities, careful processing of VIIRS observations can provide novel, objective estimates of exposure to flaring that are likely better capture exposure to air pollutants resulting from UOG operations.